1. Field of the Invention
The present invention relates to manufactured modular building structures. Specifically the invention relates to the structural components and connectors used to erect a framework comprising gridworks of interlocking polygons covered by rigid panels, column support members, and roof framing members.
2. Description of the Background Art
Manufactured structures that are fabricated in a factory and assembled on site generally means a better quality more precise structure with less time spent on site during construction. The largest application of manufactured structures is the housing industry. Approximately 10 to 15% of the new starts in housing may be classified as manufactured housing. As far back as 1972, it was predicted that manufactured or pre-engineered housing would be an intense competitor in the home building industry. This has not yet happened in the United States, although it did in Japan and in Scandinavian countries.
Besides having the potential to offer a better quality home, manufactured housing can help solve the worldwide problem of a need for affordable housing. For example, the annual housing needs of the United States require approximately 2.5 million new starts. Unfortunately, only 1.8 million units are constructed annually. This cumulative gap affects our society and the quality of life. Affordable housing will be possible when construction costs are reduced by the rapid erection of factory made components using innovative construction technology. None of the existing manufactured systems are sufficiently advanced to solve this current problem.
There are at least 500 companies in the United States offering various systems that may be considered as manufactured homes. Available types of manufactured housing are generally classified as modular, panelized, precut, and domes.
Modular homes are those shipped in sections on flatbed trucks and lifted into place by cranes onto a standard foundation prepared in advance. The modular sections arrive on the site about 90 per cent complete. Sections are joined, utilities hooked up, and siding applied. Generally, the time to complete a structure is one month. The mode of transportation limits the size of present modular systems and the customer is usually limited to selection from a few standard models.
Panelized houses include prebuilt wall sections and may also include roof and floor sections. Panels and sections are assembled, delivered by truck, and erected over a standard foundation. Manufacturer representatives erect the walls, put sections in place, and finish the house in a conventional manner. There is some design flexibility with panelized homes, but generally they appear box-like and lack architectural appeal. Precut houses are sold as packages providing all the components necessary to enclose the structure shell. Each component is cut and coded at the factory, then shipped to the site with a detailed instruction manual. Erection is done by a manufacturer representative, a builder, or the owner. The largest segment of the precut industry is log homes. The cost of building a precut home is comparable to that of conventional structures and the customer is usually limited to choosing from a set of standard designs.
A network of interlocking triangles is used to construct a dome structure. Based on R. Buckminster Fuller's geodesic dome, it is shipped as a precut and coded kit. The kit includes wood framing, plywood sheathing, steel connectors, straps, hardware, windows, and doors. Although dome structures can be very appealing, they are often disallowed by many homeowner's associations.
All of these manufactured housing types have several disadvantages including the need for a structural foundation, difficulties in transportation to the constructing site, being nearly as costly as conventional housing, use of heavy machinery to handle components at the job site, inability to readily accommodate future expansion, unacceptable appearance to existing communities, limited to a few standard models, and being restricted in architectural form. For these reasons, a general inability to provide aesthetic architectural manufactured housing at a reasonable cost exists and explains why manufactured housing still has a relatively small percentage of the housing market in the United States.
Specific objectives and advantages of the present invention over existing manufactured housing systems are:
a) to provide a modular structural system which does not require a substantial foundation; PA1 b) to provide a modular structure which supplies the first-time buyer with a basic structure and facilitates future expansion by adding modules while existing components are removed and reinstalled; PA1 c) to provide a modular structural system with a great deal of flexibility relating to room layout, architectural style, structure size, and degree of customization; PA1 d) to provide structural components which can be manufactured to withstand the rigors of transportation and be handled at the construction site without the use of heavy machinery; PA1 e) to provide a structural system in which the components can be rapidly and easily joined on site by unskilled laborers; PA1 f) to provide a structural system with improved strength characteristics over both conventional and presently available systems for manufactured housing; PA1 g) to provide a structural system which inherently provides construction precision due to characteristics of the components; and PA1 h) to provide a structural system which preserves traditional architectural values as well as takes advantage of technological developments.